Add and remove servers for monitors

The `add server` command accepts a server name and either a service name
or a monitor name. It will add servers to services and monitors. Since all
monitors use the MONITOR_SERVER structures directly, the monitors need
to be stopped before new servers are added to them

include/maxscale/monitor.h

@@ -201,7 +201,8 @@ struct monitor
 extern MONITOR *monitor_alloc(char *, char *);
 extern void monitor_free(MONITOR *);
 extern MONITOR *monitor_find(char *);
-extern void monitorAddServer(MONITOR *, SERVER *);
+extern void monitorAddServer(MONITOR *mon, SERVER *server);
+extern void monitorRemoveServer(MONITOR *mon, SERVER *server);
 extern void monitorAddUser(MONITOR *, char *, char *);
 extern void monitorAddParameters(MONITOR *monitor, CONFIG_PARAMETER *params);
 extern void monitorStop(MONITOR *);

server/core/monitor.c

@@ -258,6 +258,13 @@ monitorAddServer(MONITOR *mon, SERVER *server)
     /* pending status is updated by get_replication_tree */
     db->pending_status = 0;
 
+    monitor_state_t old_state = mon->state;
+
+    if (old_state == MONITOR_STATE_RUNNING)
+    {
+        monitorStop(mon);
+    }
+
     spinlock_acquire(&mon->lock);
 
     if (mon->databases == NULL)
@@ -274,6 +281,23 @@ monitorAddServer(MONITOR *mon, SERVER *server)
         ptr->next = db;
     }
     spinlock_release(&mon->lock);
+
+    if (old_state == MONITOR_STATE_RUNNING)
+    {
+        monitorStart(mon, mon->parameters);
+    }
+}
+
+static void monitor_server_free(MONITOR_SERVERS *tofree)
+{
+    if (tofree)
+    {
+        if (tofree->con)
+        {
+            mysql_close(tofree->con);
+        }
+        MXS_FREE(tofree);
+    }
 }
 
 /**
@@ -286,11 +310,59 @@ static void monitor_servers_free(MONITOR_SERVERS *servers)
     {
         MONITOR_SERVERS *tofree = servers;
         servers = servers->next;
-        if (tofree->con)
+        monitor_server_free(tofree);
-        {
-            mysql_close(tofree->con);
     }
-        MXS_FREE(tofree);
+}
+
+/**
+ * Remove a server from a monitor.
+ *
+ * @param mon           The Monitor instance
+ * @param server        The Server to remove
+ */
+void monitorRemoveServer(MONITOR *mon, SERVER *server)
+{
+    monitor_state_t old_state = mon->state;
+
+    if (old_state == MONITOR_STATE_RUNNING)
+    {
+        monitorStop(mon);
+    }
+
+    spinlock_acquire(&mon->lock);
+
+    ss_dassert(mon->databases);
+    MONITOR_SERVERS *ptr = mon->databases;
+
+    if (ptr->server == server)
+    {
+        mon->databases = mon->databases->next;
+    }
+    else
+    {
+        MONITOR_SERVERS *prev = ptr;
+
+        while (ptr)
+        {
+            if (ptr->server == server)
+            {
+                prev->next = ptr->next;
+                break;
+            }
+            prev = ptr;
+            ptr = ptr->next;
+        }
+    }
+    spinlock_release(&mon->lock);
+
+    if (ptr)
+    {
+      monitor_servers_free(ptr);
+    }
+
+    if (old_state == MONITOR_STATE_RUNNING)
+    {
+        monitorStart(mon, mon->parameters);
     }
 }
 

server/modules/routing/debugcli/debugcmd.c

@@ -779,15 +779,36 @@ struct subcommand failoptions[] =
 
 static void telnetdAddUser(DCB *, char *user, char *password);
 
-static void cmd_serviceAddBackend(DCB *dcb, void *a, void *b)
+static void cmd_AddServer(DCB *dcb, void *a, void *b)
 {
-    SERVICE *service = (SERVICE*)a;
+    SERVER *server = (SERVER*)a;
-    SERVER *server = (SERVER*)b;
+    char *name = (char*)b;
 
+    SERVICE *service = service_find(name);
+    MONITOR *monitor = monitor_find(name);
+
+    if (service || monitor)
+    {
+        ss_dassert(service == NULL || monitor == NULL);
+
+        if (service)
+        {
             serviceAddBackend(service, server);
+        }
+        else if (monitor)
+        {
+            monitorAddServer(monitor, server);
+        }
 
-    MXS_NOTICE("Added server '%s' to service '%s'", server->unique_name, service->name);
+        const char *target = service ? "service" : "monitor";
-    dcb_printf(dcb, "Added server '%s' to service '%s'\n", server->unique_name, service->name);
+
+        MXS_NOTICE("Added server '%s' to %s '%s'", server->unique_name, target, name);
+        dcb_printf(dcb, "Added server '%s' to %s '%s'\n", server->unique_name, target, name);
+    }
+    else
+    {
+        dcb_printf(dcb, "No service or monitor with the name '%s'\n", name);
+    }
 }
 
 /**
@@ -803,10 +824,11 @@ struct subcommand addoptions[] =
         {ARG_TYPE_STRING, ARG_TYPE_STRING, 0}
     },
     {
-        "server", 2, 2, cmd_serviceAddBackend,
+        "server", 2, 2, cmd_AddServer,
         "Add a new server to a service",
-        "Takes a server name as the parameter. The server must exist in the configuration file.",
+        "Usage: add server SERVER TARGET\n"
-        {ARG_TYPE_SERVICE, ARG_TYPE_SERVER, 0}
+        "The TARGET must be either a service or a monitor",
+        {ARG_TYPE_SERVER, ARG_TYPE_STRING, 0}
     },
     { EMPTY_OPTION}
 };
@@ -814,15 +836,34 @@ struct subcommand addoptions[] =
 
 static void telnetdRemoveUser(DCB *, char *user, char *password);
 
-static void cmd_serviceRemoveBackend(DCB *dcb, void *a, void *b)
+static void cmd_RemoveServer(DCB *dcb, void *a, void *b)
 {
-    SERVICE *service = (SERVICE*)a;
+    SERVER *server = (SERVER*)a;
-    SERVER *server = (SERVER*)b;
+    char *name = (char*)b;
+    SERVICE *service = service_find(name);
+    MONITOR *monitor = monitor_find(name);
 
+    if (service || monitor)
+    {
+        ss_dassert(service == NULL || monitor == NULL);
+
+        if (service)
+        {
             serviceRemoveBackend(service, server);
+        }
+        else if (monitor)
+        {
+            monitorRemoveServer(monitor, server);
+        }
 
-    MXS_NOTICE("Removed server '%s' from service '%s'", server->unique_name, service->name);
+        const char *target = service ? "service" : "monitor";
-    dcb_printf(dcb, "Removed server '%s' from service '%s'\n", server->unique_name, service->name);
+        MXS_NOTICE("Removed server '%s' from %s '%s'", server->unique_name, target, name);
+        dcb_printf(dcb, "Removed server '%s' from %s '%s'\n", server->unique_name, target, name);
+    }
+    else
+    {
+        dcb_printf(dcb, "No service or monitor with the name '%s'\n", name);
+    }
 }
 
 /**
@@ -837,13 +878,14 @@ struct subcommand removeoptions[] =
         "Remove account from maxadmin",
         "Remove account for using maxadmin over the network. E.g.:\n"
         "                 MaxAdmin> remove user bob somepass",
-        {ARG_TYPE_STRING, ARG_TYPE_STRING, 0}
+        {ARG_TYPE_STRING, ARG_TYPE_STRING}
     },
     {
-        "server", 2, 2, cmd_serviceRemoveBackend,
+        "server", 2, 2, cmd_RemoveServer,
-        "Remove a server from a service",
+        "Remove a server from a service or a monitor",
-        "Takes a server name as the parameter. The server must exist in the configuration file.",
+        "Usage: remove server SERVER TARGET\n"
-        {ARG_TYPE_SERVICE, ARG_TYPE_SERVER, 0}
+        "The TARGET must be either a service or a monitor",
+        {ARG_TYPE_SERVER, ARG_TYPE_STRING}
     },
     {
         EMPTY_OPTION
@@ -1331,7 +1373,7 @@ execute_cmd(CLI_SESSION *cli)
                                 }
                             }
 
-                            switch (argc)
+                            switch (cmds[i].options[j].argc_max)
                             {
                                 case 0:
                                     cmds[i].options[j].fn(dcb);